Medicinal Aerosol Formulations

ABSTRACT

The present invention provides a medical aerosol suspension formulation of MDI administration, comprising: a) micronized pa-agonist; b) micronized corticosteroid; c) a sib-therapextric quantity of a moisture-scavenger excipient; and d) a HFA propellant; wherein (a), (b), and (c) and their respective relative amounts are selected such that they associate to form floccules having a density substantially the same as that of the HFA propellant.

The present invention relates to medicinal aerosol formulations for usewith pressurised metered dose inhalers (abbreviated pMDI or MDI), andespecially improved medicinal aerosol formulations suitable for aerosoladministration.

Drugs for the treatment of respiratory diseases and disorders, such asβ₂-agonists and anti-cholinergics, corticosteroids, anti-allergies, andothers, are frequently administered directly to the lungs viainhalation. Administration via inhalation can increase the therapeuticindex and reduce side effects of the drugs compared to administration byother routes, such as orally or intravenously. Administration byinhalation can be in the form of either dry powders or aerosolformulations which are inhaled by the patient either through use of aninhalation device or as a spray.

MDIs are known devices for the administration of aerosol medicinalformulations to the respiratory tract through inhalation by the patient.The term MDI is used to describe a metered dose inhaler, of which astandard unit comprises a canister filled with the medicinalformulation, a drug metering valve and a mouthpiece. The MDI may beselectively activated by the user to deliver successive individual dosesof drug by actuation of the metering valve, such that an accuratelymetered dose of the formulation is expelled via the actuator mouthpiecefor delivery into the patient's respiratory tract.

MDI formulations are an advantageous delivery method for many reasons,including that they deliver the drug instantaneously and do not rely onthe inhalation capacity of the user. This is particularly important whenconsidering the type of condition to be treated with the drug, such asan asthma attack. Since MDI devices usually contain a sufficient amountof the medicinal formulation for multiple unit doses, it is importantthat the formulation is such that it may be successfully and repeatedlyused with a MDI device. The formulation must be delivered in a reliablemanner and in the correctly calculated dose. The formulation must alsocomply with the requirements for pharmaceutical quality, stability androbustness set out by regulatory bodies.

MDIs typically use a propellant to expel droplets or particles of theformulation as an aerosol, containing the drug, to the respiratorytract.

For a long time the propellant gases used were fluorochlorohydrocarbonswhich are commonly called Freons or CFCs, such as CCl₃F (Freon 11 orCFC-11), CCl₂F₂ (Freon 12 of CFC-12), and CCClF₂—CClF₂ (Freon 114 ofCFC-114). However it has been discovered that these CFC propellants areparticularly harmful to the environment and their production and, at thetime of writing, their use in medicinal formulations is being phasedout. An alternative propellant was therefore sought which was safe touse with inhalation drugs.

Hydrotluoroalkanes (HFAs), also known as hydro-fluorocarbons (HFCs),have been proposed as alternative propellant gases, because they containno chlorine and are considered to be less destructive to the atmosphere.In particular 1,1,1,2-tetrafluoroethane (HFA 134a) and1,1,1,2,3,3,3-heptafluoropropane (HFA 227) have been found to be goodreplacement propellants for the CFC propellants and a number ofmedicinal aerosol formulations using these propellants have beenproposed.

Formulations administered via MDIs can be in the form of solutions orsuspensions. In suspension formulations the drug is manufactured as afine particle powder which is then suspended in a liquefied propellantor propellant blend. The suspension formulation can be stored in asealed canister with sufficient pressure to maintain the propellant inliquid form. For example, the vapour pressure for a HFA227 formulationmay typically be around 1.96 bar at 0° C., 3.90 bar at 20° C. and 7.03bar at 40° C. In solution formulations the drug is solubilised in theliquefied propellant phase. When the metering valve is actuated, a doseis delivered in rapidly deployed fine droplets.

Suspension formulations are usually preferred because of generallyimproved chemical stability of the suspended particles in comparison tosolubilised drugs. Stability problems associated with the chemicaldegradation of solubilised drug compounds are known in the art.

In order that a medicinal formulation is suitable for use with an MDIdevice, the particle size of the deployed aerosol must be small enoughthat it can be inhaled into the lungs of the users, be that a grownadult, child or elderly/infirm person. Therefore, the particles of thesuspension formulation need to be microfine with a mean aerodynamicparticle diameter (measured as Mass Median Aerodynamic Diameter (MMAD))of about 1 to 10 μm, and preferably 1 to 6 μm. Micronised particles ofthis size can be obtained by various methods known in the art, forexample mechanical grinding or spray drying.

The amount of active drug deployed in fine, inhalable particles iscalled the fine particle dose (FPD) or the fine particle fraction (FPF),which is defined as the percentage of the fine particle dose relative tothe total amount of released active compound. Both are determined by themeasurement of the aerodynamic particle size distribution with a cascadeimpactor or liquid impingers. These are routine tests for which themethods and apparatus are described in the pharmacopeias. For example,formulations of the present invention meet the requirement set out inChapter <601> of the United States Pharmacopeia (USP) 32 or in theinhalants monograph 2.9.18 of the European Pharmacopeia (Ph.Eur.),6^(th) edition 2009.

Microfine particles for use in suspension formulations do, however, havesome associated drawbacks. They have a large surface area and thereforean unfavourable ratio of surface area to volume or mass. This ratioresults in strong interaction forces between the particles andundesirable powder cohesion and adhesion tendencies. This in turn canlead to difficult handling due to poor flow rate of the powdered drugduring manufacture and poor suspension properties of the MDIformulation. Such powders are therefore difficult to formulate for usewith a MDI device, difficult to handle and are strongly influenced byelectrostatic charge, processing methods, humidity, etc.

Formoterol fumarate dihydrate (hereafter called formoterol) is a longacting β₂-agonist bronchodilator (β-sympathomimetic) commonly used forthe relief of asthma symptoms. Fluticasone propionate (hereafter calledfluticasone) is a potent synthetic corticosteroid which is also oftenprescribed as a treatment for asthma, chronic obstructive pulmonarydisease and allergic rhinitis. Both are examples of drugs which can beindividually delivered via a MIN product.

Formoterol and fluticasone (but in particular formoterol) are eachnotoriously difficult compounds to be formulated for use with MDIs. Onereason for this is because the potency of these drugs means that only avery small dose should be delivered in each case and the concentrationof the drug within the HFA formulation is therefore very low. Thisexacerbates the problems highlighted above with regard to themanufacture of the aerosol formulation and the pharmaceutical quality,stability and robustness of the aerosol formulation, as required by theregulatory authorities, can therefore be compromised. Robustness of theformulation may be determined when handled by the patient, underdifferent conditions of use, upon prolonged storage or upon storageunder stress conditions (e.g. freeze-thaw cycles). Due to the lowconcentration of drug present within the formulation, fluctuations inthe local homogeneity of the drug suspended in the propellant (i.e., ina volume range of about 50 μL) can result in deviation in the delivereddose.

It has also been shown that MDI formulations comprisinghydrofluoroalkanes (UFAs) as propellants are difficult to formulatebecause there are only a limited number of currently known suspensionaids that are regarded as safe for inhalation, which can be employed toreduce undesirable particle cohesion and adhesion tendencies and toimprove the physical stability of the suspension formulation using suchHFA propellants.

Furthermore, chemical stability of the HFA formulations is particularlya problem when bronchodilator β₂-agonists, such as formoterol, are usedowing to their susceptibility to oxidative and hydrolytic conditions.Hydrolysis is one of the major identified factors affecting degradationof formoterol under stress conditions (e.g. 40° C./75% relativehumidity) because such formulations are usually sensitive to moistureand are susceptible to the ingress of moisture from the surrounding air.

Slight concentration changes or changes in the physical stability of theMDI suspension which may occur during storage due to temperature changesand/or moisture ingression may lead to significant differences in themetered and delivered doses (e.g. dose uniformity failures). Thesedifferences may also be seen as a reduction in the inhalable proportionof the released dose, which is determined in vitro as the FDP or FPF.

This reduction may be caused by strong adsorption of drug particles tointernal surfaces of the container closure system (canister and meteringvalve) and by agglomeration of microfine particles as a result ofimperfect suspension stability. It is found that water molecules, whichmay accumulate in the MDI formulation during long term storage and use,are particularly detrimental to the suspension since they interact withthe polar drug particles and result in a stronger binding between theparticles.

In view of the above described problems, it is generally thought to bekey to prevent ingression of water to reduce hydrolysis of formoterolformulations.

Cromolyn sodium (DSCG) is an excellent internal moisture scavenger and asuspension enabler. It has been used for administration via theinhalation route and has been demonstrated to be clinically safe.However, it has been shown that cromolyn sodium itself has a biologicalpharmacological effect and so its use in the HFA formulations describedabove has previously been avoided so that an effect over and above thatof the fluticasone and formoterol is not seen.

The type of propellant used also has an effect on the actuation of themetered dose inhaler. The use of HFA propellants instead of CFCpropellants has led to a further problem with the fine particles ofsuspended drug. This is because the HFA propellants have a higherpolarity than the CFC propellants previously used, which causes the HFAsuspension formulations to be comparatively more susceptible to physicalstability problems. When active agents are used that have a densitylower than that of the liquid in which they are placed then they have atendency to float and cream which can lead to an irregularity in thedosage delivered. The drugs also frequently adhere to the inside surfaceof the device and the dosage mechanism.

This deposition on the walls of the metering valve has been found to besignificantly increased compared to the CFC propellant. This depositioncan lead to a reduction in the actual dose dispensed. This adherence canalso lead to the device failing owing to a clogging of the internalmechanisms of the canister or blockage of the metering valve.

Previously proposed devices have used a container in which the interiorsurfaces are coated with fluorocarbon polymer plastics; seeWO-A-96/32150 and U.S. Pat. No. 6,596,260. However, the problems withsuch systems include that the fluorocarbon polymers, and theirconstituents, can be soluble in the propellants used in the aerosolformulations. Also such coatings themselves need to undergo safety testsand product formulation development in order to give a safe and stableproduct. These tests further add to the production cost which adds tothe overall cost of the product.

Coating the internal surfaces of the containers to prevent adsorptionalso causes problems with regard to the use of certain metals for thecanister. The most commonly used metals for the canister are aluminiumalloys. The plastics coating must undergo heat treatment in order to becured which results in the strength of the container being compromisedbecause the metal canister layer becomes softer and malleable from theheat.

The plastics coating material itself can also lead to contamination ofthe medicinal formulation because there is the potential for leachablecompounds to find their way into the formulation contained within thecanister. Such leachable compounds can lead to degradation of the drugcompound within the medicinal formulation and a less effective and lessrobust product. The shelf-life of the product may also be compromisedwith degradation of the active ingredients upon storage.

There are, therefore, a number of important parameters that need to beconsidered when producing a medicinal aerosol formulation for use with aMIN.

Some of the difficulties in formulating fluticasone propionate andformoterol fumarate within a single formulation have been addressed inWO 2005/034911 by the introduction of a drying step to dry theformoterol fumarate prior to mixing it together with the otheringredients. However, the problems associated with long term storage ofsuch formulations have not been addressed.

The present application seeks to alleviate at least some of theaforementioned problems with the prior art.

Accordingly, a first aspect of the present invention is directed to amedicinal aerosol suspension formulation for MDI administration,comprising (a) a micronised β₂-agonist, (b) a micronised corticosteroid,(c) a sub-therapeutic quantity of a moisture-scavenger excipient, and(d) a HFA propellant wherein (a), (b) and (c) and their respectiverelative amounts are selected such that they associate to form flocculeshaving a density substantially the same as that of the HFA propellant.

It has been found that the constituents of the present formulation tendto associate in such a way as to form floccules (also known as flocs,flocculi or flocculates). Floccules comprise a loosely held mass oraggregation of discrete fine particles held together in a network-likefragile structure, suspended in solution. The aggregates formed by thefloccules tend to break up easily under the application of small amountsof sheer stress, such as gentle agitation of the canister, and reform anextended network of particles after the force is removed. Flocculation,therefore, imparts a structure to the suspension with virtually noincrease in viscosity. In contrast to deflocculated systems, thefloccules will settle rapidly, usually to a high sediment volume and maybe easily re-suspended even after standing for prolonged periods ofstorage, for example after 3, 6, 9 or 12, 18 months or longer.

It has been found that, once associated, the floccules of the presentformulation have a density to match that of the density of thepropellant in which they are placed. This gives the floccules theability to remain in suspension without the tendency to cream, float orsink. The suspension formulation of the present invention may thereforeremain in a viable formulation for an extended period of time andresults in a robust product with an extended shelf life and improvedreliability of the end product.

Furthermore, the tendency to form these floccules may provide enhanceduniformity in the suspension and less fluctuation in the localhomogeneity which then results in a product which may have reduceddeviation in the delivered dose.

In addition to the above, the floccules afford an increased stability tothe suspension formulation. This increased stability of the suspensionmeans that the ingredients associate together in preference toassociating with the internal surfaces of the canister or metering valveof the inhaler. Therefore there is a reduced tendency to adhere to theinside of the container or the metering valve of the canister throughwhich the suspension formulation must pass. This may lead to an increasein the reliability of the delivered dose. In addition there are fewertendencies to block the actuation mechanism and the metering valve,which in turn provides for a formulation which can be reliably andrepeatedly dispensed at the correct amount.

Typically, suspension formulations, especially MDI suspensionformulations using HFA propellants are inherently physically unstable.The formulations form two phases, a liquid propellant phase and asuspended particulate phase, which segregate as a result ofgravitational force. Within the canister, areas having differentconcentrations of suspended particles may also exist as a result ofsmall temperature fluctuations inside the canister which leads tothermal motion of particles. However, the tendency of formulationsaccording to the present invention to associate to form flocculesresults in all the active ingredients remaining associated right upuntil the moment they are dispensed from the MDI and enter the patient'srespiratory system. This provides for a formulation with an improvedquality and improved ability to adhere to a calculated dose.

Preferably the HFA propellant is HFA 227, HFA 227 is an inert propellantwith low toxicity and is suitable for use in metered-dose inhalers. HFA227 propellant, when combined with a small amount of ethanol to form theliquid propellant phase has a calculated density, over a range oftemperatures, as follows:

Temp. Calculated density of [g/ml] 10° C. 1.45 15° C. 1.43 20° C. 1.4122° C. 1.40 25° C. 1.39 30° C. 1.36

The above numbers were calculated using thermodynamic laws on idealmixtures. However, in practice the liquid mixtures are likely to behaveas non-ideal mixtures and the “true” densities may be slightly differentto the calculated values.

It is therefore advantageous to have a formulation wherein the averagedensity of the floccules (comprising the micronised β₂-agonist,micronised corticosteroid and moisture-scavenger excipient) issubstantially the same as the density of the propellant ±0.2 g/cm³,preferably ±0.1 gcm³, more preferably ±0.05 g/cm³ of the propellant.

The average density of the floccules may be calculated using anystandard technique, for example by determining the true particle densityof each solid component by helium pycnometry. The density of thefloccules may therefore substantially match that of the density of thepropellant over a range of temperatures of 10° C. to 30° C. under whicha MDI would usually be operated by a user.

Preferably the corticosteroid is fluticasone propionate or apharmaceutically acceptable salt thereof. The corticosteroid isadvantageously present in an amount of 0.01-0.6% by weight; preferablybetween 0.02-0.5% by weight; and more preferably 0.03-0.4% by weight,based on the total weight of the formulation. This is the advantageousamount in order to be effective in use and also to form the correctdensity of floccules for suspension in the propellant.

The corticosteroid preferably has a defined particle size of less than10 μm for 100%, less than 6 μm for 90%, less than 3 μm for 50%, and lessthan 2 μm for 10% of the particles.

Preferably the β₂-agonist is formoterol fumarate dihydrate or apharmaceutically acceptable salt or derivative thereof. The β₂-agonistis preferably present in an amount of 0.003-0.04% by weight; preferably0.004-0.03% by weight; and more preferably 0.005-0.02% by weight, basedon the total weight of the formulation. In a preferred embodiment,formoterol fumarate dihydrate may be employed in an amount of0.003-0.008% by weight, based on the total weight of the formulation. Inan alternative preferred embodiment, formoterol fumarate dihydrate maybe employed in an amount of 0.01-0.04% by weight, based on the totalweight of the formulation. As with the corticosteroid, this is theadvantageous amount of β₂-agonist in order to be able to be effective inuse and also to form the correct density of floccules for suspension inthe propellant.

The β₂-agonist preferably has a defined particle size of less than 10 μmfor 100%, less than 6 μm for 90%, less than 3 μm for 50%, and less than2 μm for 10% of the particles.

Preferably, the moisture scavenger excipient is sodium cromolyn (DSCG)and is advantageously present at sub-therapeutic levels such that itdoes not exert a biological effect itself and is pharmaceuticallyinactive. The moisture scavenger is therefore suitably present in anamount of 0.01-0.1% by weight; preferably 0.016-0.09% by weight; morepreferably 0.02-0.08% by weight; more preferably 0.025-0.07% by weight;more preferably 0.03-0.05% by weight; more preferably 0.03-0.04% byweight, based on the total weight of the formulation.

The moisture scavenger preferably has a defined particle size of lessthan 10 μm for 100%, less than 6 μm for 90%, less than 3 μm for 50%, andless than 2 μm for 10% of the particles.

It has been found that DSCG is an excellent suspension enabling agentwhen used in formulations including a HFA propellant. DSCG itselfconsists of particles which encourage and allow the formation ofheterogeneous floccules with the active agents.

DSCG acts to aid stabilisation of the formulation, particularly againsthydrolysis by competitive water absorption. DSCG exists as a singlecrystal form that is non-stoichiometric with regard to water content andadsorbs or desorbs water rapidly in response to changes in relativehumidity. DSCG crystals are universal in the extent of reversible waterabsorption without collapse of the crystal lattice and can absorb up to9 molecules of water per mol, which is about 24% w/w. The crystalstructure analysis by X-ray diffraction reveals the existence ofchannels that are capable of reversibly accommodating a variable numberof water molecules (depending on the ambient relative humidity) withonly small dimensional changes within the lattice. Despite its largemoisture adsorption capacity DSCG is not deliquescent (like, forexample, sodium sulphate) but is solid in the range of 10 to 90% r.h.

In the present invention DSCG acts to stabilize the fine particlefraction (FPF) in the formulation by competitively binding free (i.e.molecular dissolved) water present within the propellant phase. Thisassists in stabilising the fine particle fraction by preventingagglomeration of suspended particles (i.e. formation of liquid and/orcrystal bridges) and particle growth (i.e. Ostwald ripening) onstability. This allows for a more robust product during storage and useas the formulation has improved tolerance to the presence of internalwater. For example, up to 600 ppm of total internal water may betolerated. Furthermore this allows for a much longer ‘use period’ oncethe product is in the patients hands. In addition, there is a reducedtendency to adhere to surfaces, which allows the medicinal formulationto be used with an uncoated canister instead of a canister which has itsinternal surfaces coated with a polymer.

Preferably the medicinal aerosol suspension formulation furthercomprises a wetting agent; more preferably the wetting agent is adehydrated alcohol; and most preferably the wetting agent is ethanolwhich may be present in an amount of 0.01-3% by weight; preferably0.05-2.5% by weight; and more preferably 1.0-2.0% by weight, based onthe total weight of the formulation.

A wetting agent facilitates the wetting of the active agents within theliquefied propellant and thus the suspension manufacture such that theactive agents do not become partially solubilised. The addition of suchagents requires a delicate balancing act between allowing the activeagents to become wetted without being partially solubilised and causingthem to be partially solubilised such that Ostwald ripening, particlegrowth and, eventually, stability failures occur.

Ethanol can be added in small quantities as it also helps to prevent thedeposition of the active agents on the walls of the canisters andmechanical parts.

In a preferred form, the formulation of the present invention thereforecomprises as pharmaceutically active ingredients formoterol andfluticasone and as pharmaceutically inactive ingredients sodiumcromolyn, HFA 227 and ethanol.

A further aspect of the present invention is directed to apharmaceutical composition comprising, 0.01-0.6% by weight of micronisedcorticosteroid; 0.003-0.04% by weight of micronised β₂-agonist; and0.01-0.1% by weight of sodium cromolyn.

Preferably the corticosteroid is micronised fluticasone propionate.

Advantageously the β₂-agonist is micronised formoterol fumaratedihydrate.

Preferably the pharmaceutical composition further comprises a wettingagent, more preferably the wetting agent is a dehydrated alcohol, mostpreferably ethanol. Preferably the wetting agent is present in an amountof 0.01-3% by weight; preferably 0.05-2.5% by weight; and morepreferably 1.0-2.0% by weight, based on the total weight of theformulation.

A further aspect of the present invention is directed to apharmaceutical suspension formulation comprising about 0.003-0.04%formoterol fumarate dihydrate, about 0.01-0.06% fluticasone propionate,about 0.01-0.1% suspension agent and about 0.01-3% dehydrated alcohol.

Preferably the suspension agent is sodium cromolyn (DCSG) which alsoallows the active agents to remain in the suspension state for aprolonged period of time. This improves the shelf-life of the product asit can be effective for a longer time after production.

Furthermore, DECO acts as a ‘bulking agent’, since its use increases theconcentration of particles suspended in the formulation, thereforeminimising inherent concentration changes in the suspension without theneed for the addition of other excipients. DSCG also provides the usualbenefits of bulking agents, namely affording the preparation of a morehomogeneous suspension, which leads to improved accuracy of the dose.

A further aspect of the present invention is directed to a productcontaining formoterol fumarate dihydrate, fluticasone propionate andsodium cromolyn as a combined preparation for separate, sequential orsimultaneous use in the treatment of inflammation and preferably for thetreatment of asthma and allergic rhinitis.

A further aspect of the present invention is directed to the use ofsodium cromolyn in the preparation of a pharmaceutical suspensionformulation in HFA propellant comprising fluticasone propionate andformoterol fumarate dihydrate microparticles for forming floccules offluticasone propionate, formoterol fumarate dihydrate and sodiumcromolyn having a density substantially the same as that of the HFApropellant.

According to a further aspect of the present invention, there isprovided the use of 0.01 to 0.1% sodium cromolyn in the preparation of apharmaceutical suspension formulation in HFA propellant comprising 0.01to 0.6% fluticasone propionate and 0.003 to 0.04% of formoterol fumaratedihydrate microparticles for forming floccules of fluticasonepropionate, formoterol fumarate dihydrate and sodium cromolyn having adensity substantially the same as that of the HFA propellant.

Preferably, the average density of the floccules is substantially thesame as the density of the HFA propellant ±0.2 g/cm³, preferably ±0.1gcm³, more preferably ±0.05 g/cm³ of the propellant.

Preferably, the pharmaceutical suspension formulation additionallycomprises a wetting agent, preferably a dehydrated alcohol, preferablyethanol.

According to a further aspect of the present invention, there isprovided a method of increasing the stability of a medicinal aerosolsuspension formulation of a micronised β₂-agonist and a micronisedcorticosteroid in HFA propellant over a prolonged period of storage,comprising the addition of a sub-therapeutic amount of sodiumcromoglycate, wherein the respective relative amounts of the micronisedβ₂-agonist, micronised corticosteroid and sodium cromoglycate areselected such that they associate to form floccules having a densitysubstantially the same as that of the HFA propellant.

Preferably the prolonged storage is for 3, 6, 9, 12 or 18 months.Preferably the water content of the suspension formulation afterprolonged storage is in the range of 500 ppm to 800 ppm, preferably 600ppm to 700 ppm.

Examples of suitable dosage strengths of a pharmaceutical composition inaccordance with the present invention may be found in the followingtable.

TABLE 1 Composition of examples of dosage strengths of the formulation %w/w. Flutiform 25/5 Flutiform 50/5 Flutiform 125/5 Flutiform 250/5Nominal dose 50 mcg FP and 100 mcg FP and 250 mcg FP and 500 mcg FP and10 mcg FF 10 mcg FF 10 mcg FF 10 mcg FF Fluticasone 0.0357 0.0714 0.17850.3570 Formoterol 0.0071 0.0071 0.0071 0.0071 Cromolyn sodium 0.03430.0343 0.0343 0.0343 Ethanol 1.43 1.43 1.43 1.43 HFA 227 qs ad 100.0 qsad 100.0 qs ad 100.0 qs ad 100.0 Flutiform 250/10 Flutiform 250/10Nominal dose 500 mcg FP 500 mcg FP and and 20 mcg FF 20 mcg FFFluticasone 0.3570 0.3570 Formoterol 0.0142 0.0142 Cromolyn sodium0.0343 0.0686 Ethanol 1.43 1.43 HFA 227 qs ad 100.0 qs ad 100.0

Following is a description by way of example only with reference to theaccompanying drawings of embodiments of the present invention.

In the drawings:

FIG. 1—Aerodynamic particle size distribution for fluticasone andformoterol.

FIG. 2—Photographs of Suspension in Glass Vials at Different Time Pointsafter Shaking.

EXAMPLES Example 1

The following compositions shown below in Table 2 were made up and thedensity of the floccules of fluticasone, formoterol and cromolyn sodiumwere calculated and compared to the calculated density of the liquidphase (comprising 1.43% w/w of anhydrous ethanol and HFA 227) over arange of temperatures.

TABLE 2 Compositions of pharmaceutical formulations. Flutiform FlutiformFlutiform Flutiform 25/5 50/5 125/5 250/5 Flutiform 250/10 Nominal 50mcg FP 100 mcg FP 250 mcg FP 500 mcg FP 500 mcg FP and 20 dose and 10mcg and 10 mcg and 10 mcg and 10 mcg mcg FF FF FF FF FF Fluticasone0.0357 0.0714 0.1785 0.3570 0.3570 Formoterol 0.0071 0.0071 0.00710.0071 0.0142 Cromolyn 0.0343 0.0343 0.0343 0.0343 0.0343 sodium Ethanol1.43 1.43 1.43 1.43 1.43 HFA 227 qs ad 100.0 qs ad 100.0 qs ad 100.0 qsad 100.0 qs ad 100.0

The density of the liquid phase was determined based on thethermodynamic laws on ideal mixtures. However, in practice the liquidmixtures are likely to behave as non-ideal mixtures and the “true”densities may be slightly different to the calculated values.

The average density of the floccules was determined by measuring thetrue particle density of each solid component by helium pycometry.

The results of the density calculations are shown in Tables 3 and 4.

TABLE 3 Calculated density of liquid phase. Calculated density of liquidTemp. phase [g/ml] 10° C. 1.45 15° C. 1.43 20° C. 1.41 22° C. 1.40 25°C. 1.39 30° C. 1.36

TABLE 4 Calculated density of floccules Composition Calculated densityof floccules (g/ml) Fluticasone/formoterol 25/5 (25 μg 1.47 fluticasoneand 5 μg of formoterol per actuation) Fluticasone/formoterol 50/5 1.43Fluticasone/formoterol 125/5 1.40 Fluticasone/formoterol 250/5 1.38Fluticasone/formoterol 250/10 1.38

It can be seen from the above results in Tables 3 and 4 that the averagedensity of the floccules substantially matches the calculated density ofthe liquid phase within ±0.2 g/ml.

Example 2

The batches shown in Table 5 were made up and tested (over a range of‘use temperatures’ from 10 to 30 degrees Celsius):

TABLE 5 Composition of Batch 1 and Batch 2. Description Batch 2 Batch 1Fluticasone/formoterol Fluticasone/formoterol formulation formulationwithout DSCG (nominal dose 100 μg (for comparison, fluticasone/ not partof the 10 μg formoterol) present invention) Composition % w/w g % w/w gFluticasone 0.0714 2.340 0.0714 2.340 propionate Formoterol 0.0071 0.2340.0071 0.234 fumarate dihydrate Cromolyn sodium 0.0343 1.123 0.00000.000 (DSCG) Ethanol 1.43 46.8 1.43 46.8 HFA 227 qs to 100.0 3225.5 qsto 100.0 3226.6

The size of each batch was 3.3 kg (approximately 300 units). Ethanol96.5% w/w (97.75% v/v) was used to challenge the formulation with awater level which was about similar to the amount contained in theformulation at the end of the envisaged shelf-life. The water content ofall raw materials except HFA 227 was determined by Karl-Fischer analysisprior to preparation of the suspension.

The appropriate amounts of the micronised active substances were weighedand transferred into the batching vessel. The appropriate amount ofsodium cromolyn, (DSCG) was added and the vessel closed. The propellantmixture of HFA 227 (apaflurane) with 1.45% alcohol was made in aseparate vessel and transferred into the batching vessel. The solidmaterials were dispersed in the liquefied propellant by use of arotor-stator homogenizer at 2900 rpm for 30 min. The homogeneous bulksuspension was cooled to 4° C. and re-circulated between the vessel andthe Pamasol aerosol filling machine P2001.

Pharmaceutical aerosol canisters with 14 ml brimful volume were crimpedwith 50 mcl metering valves using a Pamasol P2005 crimping machine.Aliquots of 11±0.5 g suspension were filled into the crimped canistersby the P2001 filling machine. The weight of each filled canister waschecked; all filled canisters were subjected to a heat stress test at56° C. and stored one month prior to assembly with the actuator fortesting.

Glass vials were filled in addition to the above canisters with thefluticasone/formoterol formulations of Batch 1 and Batch 2 HFA-MDI toassess suspension stability visually and by time lapse photography, seeFIG. 2. The glass vials were shaken and photographs were taken 15seconds, 30 seconds, 45 seconds, 1 minute, 1 minute 30 seconds, 2minutes, 3 minutes, 5 minutes and 2 hours after this agitation.

The following analytical tests were performed in relation to Batch 1 and2:

TABLE 6 Tests performed. Table in which results are Description Methoddisplayed. Drug content (assay) HPLC Table 7 Dose content uniformity(inter-inhaler) HPLC Table 8 Dose content uniformity through HPLC Table9 canister life (intra-inhaler) Particle size distribution (by AndersenHPLC FIG. 1 cascade impactor) Water content Karl Fischer Table 7Interaction between content and container HPLC Table 10 (canister andvalve) Suspension stability (in filled glass vials) Time lapse FIG. 2photography

TABLE 7 Drug, DSCG and water content of Fluticasone/formoterolformulation 100/10 Batches 1 (Fluticasone/formoterol formulation 100/10with DSCG) and 2 (without DSCG) upon release from the MDI. Batch No. 1 2Mean fluticasone content [μg 679.0/95.1% 658.0/92.2% per g suspension/%of target] (0.4%) (4.6%) (RSD %, n = 3) Mean formoterol content [μg 68.2/95.5%  64.7/90.6% per g suspension/% of target] (0.4%) (5.3%) (RSD%, n = 3) Mean DSCG content [μg per 321.0/93.7% N.A. g suspension/% oftarget (0.3%) (RSD %, n = 3) Mean water content [ppm] 672 (12.6%) 624(5.1%) (RSD %, n = 3)

Table 7 shows the water content of the batches when ethanol 96.5% w/wwas included in the formulation, thereby adding 500 ppm to theformulation in addition to the moisture typically present due to themanufacture process itself. The slightly higher value for Batch 1 mayhave been due to the presence of DCSG. The water level found in the twobatches is that as would typically be expected after long-term storageof the product or after shorter term storage in humid conditions (e.g.,75% RH or higher). The values obtained therefore demonstrate that theformulations of Batch 1 and Batch 2 (or other equivalent batchesproduced in the same way using ethanol 96.5% w/w) can be used todemonstrate the effect of inclusion of DCSG within a formulation offluticasone/formoterol on the parameters listed within Table 6, above,as would be found, for example, after long-term storage of theformulation.

It can be seen that the drug concentration for the formulation with DCSGwas higher than that of Batch 2 with 95.1% of target fluticasone and95.5% of target formoterol content achieved with DCSG in comparison to92.2% and 90.6% respectively without DCSG. This could be associated withdrug losses during manufacturing due to drug absorption on themanufacturing equipment.

TABLE 8 Dose content uniformity (inter-inhaler) ofFluticasone/formoterol formulation 100/10 batches 1(Fluticasone/formoterol formulation 100/10 with DSCG) and 2 (withoutDSCG) upon release from the MDI. Batch No. 1 2 Mean delivered dose of92.0 (5.2%) 79.0 (4.7%) fluticasone [μg] (RSD %, n = 10) Mean delivereddose of  8.9 (6.0%)  7.4 (4.8%) formoterol [μg] (RSD %, n = 10)

Table 8 shows the results of testing dose delivery from 10 inhalers foreach Batch. The inclusion of DCSG within the formulation is shown todeliver a higher dose of both drugs (e.g. 92% with DCSG in comparison to79% without for fluticasone).

TABLE 9 Dose content uniformity through canister life ofFluticasone/formoterol formulation 100/10 batches 1(Fluticasone/formoterol formulation 100/10 with DSCG) and 2 (withoutDSCG) upon release from the MDI. Batch No. 1 2 Mean delivered dose of89.6 (8.0%) 79.9 (3.8%) fluticasone [μg] (RSD %, n = 9) Mean delivereddose of formoterol [μg] (RSD %,  8.8 (7.7%)  7.5 (5.5%) n = 9)

The results of the dose content uniformity study during the life of thecanister, as shown in Table 9, also shows that a higher dose of bothdrugs is delivered by Batch 1 (with DCSG) (89.6% with DCSG in comparisonto 79.9% without for fluticasone).

TABLE 10 Drug and DSCG residue in canister and on valve after exhaustionof Fluticasone/formoterol formulation 100/10 batches 1(Fluticasone/formoterol formulation 100/10 with DSCG) and 2 (withoutDSCG) upon release from the MDI. Can Valve Total Batch 1 Formoterolassay [μg] 31.2 (13.4%) 31.9 (21.3%) 63.1 (13.8%)  (RSD %, n = 3)Fluticasone assay [μg]  330 (14.7%)  278 (22.3%) 608 (13.5%) (RSD %, n =3) DSCG assay [μg] 74.8 (16.9%) 69.4 (23.0%) 144 (15.1%) (RSD %, n = 3)Batch 2 Formoterol assay [μg] 51.4 (17.2%) 62.7 (14.0%) 114.1 (15.1%)  (RSD %, n = 3) Fluticasone assay [μg]  539 (16.5%)  561 (16.7%) 1100(15.8%)  (RSD %, n = 3) DSCG assay [μg] N.A. N.A. N.A. (RSD %, n = 3)

The above table shows that nearly twice as much of both drugs wasrecovered from canisters and valve of Batch 2 in comparison to Batch 1(with DCSG) (e.g. 608 μg of fluticasone recovered for Batch 1, comparedwith 1100 μg for Batch 2).

FIG. 1 shows the aerodynamic particle size distribution results of testsperformed on five inhalers for each batch. Similar to the dose deliveryresults in Tables 4 and 5, less fluticasone and formoterol weredelivered from the actuator for Batch 2 in comparison to Batch 1.

FIG. 2 shows the results of time-lapse photography for glass vialscontaining formulations of the two batches. The glass vials were alsovisually examined and the following differences in suspension stabilitywere found.

Batch 1 (with DSCG) exhibited large loose floccules soon after cessationof agitation (this result was different from that seen when theformulation is not challenged with water) while Batch 2 (without DSCG)remained more disperse and more homogeneous.

After a longer period of time, however, Batch 1 remained in the looselyflocculated form, resulting in a bulky but readily redispersiblesediment while Batch 2 appeared to form agglomerates of differentdensities, some of which sedimented and others of which floated. Atleast part of the sedimented material present within the glass vial ofBatch 2, which formed a creamed material deposited on the glass vialsurface at the liquid-gas interface, was difficult to redisperse into ahomogeneous suspension.

Visual examination therefore revealed that Fluticasone/formoterolformulation with DSCG (Batch 1) floccules more rapidly than the sameformulation when not challenged by additional water, but remainedhomogeneous long enough to provide a satisfactory and consistent doseuniformity. In contrast, the formulation without DSCG prepared forcomparison (Batch 2) creamed rapidly and resulted in drug deposition onthe glass vial surface at the liquid-gas interface. These visualobservations therefore provide evidence that the formulation of thepresent invention is able to tolerate high amounts of internal water.

In conclusion, the use of DSCG as an enabling excipient inFluticasone/formoterol formulation HFA-MDI thus provided a more robustfinished drug product, particularly against moisture ingress, whichoccurs unavoidably during storage and use.

Example 3

The following batch was made up using the process described in Example1:

TABLE 11 Batch 3 composition Description Batch 3 Fluticasone/formoterolformulation (nominal dose 250 μg fluticasone/ 12 μg formoterol)Composition % w/w g Fluticasone propionate 0.1785 3.900 Formoterolfumarate dihydrate 0.0086 0.187 Cromolyn sodium (DSCG) 0.0343 0.749Ethanol 1.43 31.2 HFA 227 qs to 100.0 2148.0

The filled unpouched inhalers were put into an investigational stabilityprogram for 6 months at 40° C./75% RH and Showed good product qualityand robustness in the product performance tests, as shown by the resultsof Tables 12 and 13, below.

TABLE 12 Results of Andersen Cascade Impactor of fluticasone/formoterolformulation (250 μg fluticasone/12 μg formoterol) at release and after 1to 6 months storage at 40° C./75% RH. Release 1 Month 3 Months 6 MonthsBatch 3 Mean (RSD 40° C./75% RH 40° C./75% RH 40° C./75% RH Fluticasone%, n = 4) Can 1 Can 2 Can 1 Can 2 Can 1 Can 2 Delivered dose [μg, 2  197(7.2%) 173.1 191.5 184.5 203.7 189.0 173.8 actuations]   Metered dose[μg, 2  211 (8.4%) 198.5 207.2 204.7 216.6 229.5 n.d. actuations]   Fineparticle dose [μg,  102 (8.5%) 79.7 83.7 80.0 86.0 102.7 73.4 2actuations] Fine particle fraction 52.0 46.1 43.7 43.3 42.2 54.3 42.2 [%based on delivered dose] Fine particle fraction 48.5 40.2 40.4 39.1 39.744.7 n.d. [% based on metered dose] Formoterol Delivered dose [μg, 2 9.5 (5.1%) 8.6 9.5 9.8 10.5 8.4 7.9 actuations] Metered dose [μg, 210.9 (5.3%) 11.5 11.3 12.7 12.5 10.5 n.d. actuations] Fine particle dose[μg,  5.6 (8.3%) 5.3 5.7 5.6 6.0 5.4 3.8 2 actuations] Fine particlefraction 58.4 61.6 60.0 56.4 57.2 63.6 48.6 [% based on delivered dose]Fine particle fraction 51.1 46.0 50.6 43.6 47.8 51.3 n.d. [% based onmetered dose]

TABLE 13 Results of delivered dose uniformity test through inhaler lifeof fluticasone/formoterol formulation (250 μg fluticasone/12 μgformoterol) at release and after 1 to 6 months storage at 40° C./75% RH.1 Month 3 Months 6 Months 40° C./ 40° C./ 40° C./ Release 75% RH 75% RH75% RH Batch 3 N = 10 N = 12 N = 10 N = 12 Mean delivered  197 (3.7%) 208 (4.0%) 190 (11.7%) 191 (5.9%) fluticasone dose [μg/2 actuations](RSD %) Mean delivered 10.2 (7.0%) 10.4 (4.3%)  9.3 (12.3%)  9.2 (5.8%)formoterol dose [μg/2 actuations] (RSD %)

Example 4

The following batches were made up using the process described inExample 1:

TABLE 14 Composition of Batch 4 and Batch 5. Description Batch 4 Batch 5Fluticasone/formoterol Fluticasone/formoterol formulation formulation(nominal dose 500 μg (nominal dose 500 μg fluticasone/20 μgfluticasone/10 μg formoterol) formoterol) Composition % w/w % w/wFluticasone propionate 0.3571 0.3571 Formoterol fumarate 0.0143 0.0071dihydrate DSCG 0.0343 0.0343 Ethanol 1.43 1.43 HFA 227 qs to 100.0 qs to100.0

The results of the stability investigation up to 12 months demonstratedgood product quality and robustness of both formulations, as shown bythe results displayed in Tables 15 and 16, below.

TABLE 15 Summary of ACI results of fluticasone/formoterol formulationFlutiform 250/10 (Batch 4) up to 12 months at 25° C./60% RH and 40°C./75% RH. Each result is the mean of 6 determinations (beginning andend of 3 canisters). 25° C./60% RH 40° C./75% RH Fluticasone Initial 3months 6 months 12 months 1 month 3 months 6 months 12 months Metered428.9 419.8 426.8 427.7 425.9 454.8 429.3 437.1 412.6 442.3 449.8 430.0431.2 447.9 dose [μg] Delivered 407.5 400.9 407.3 413.9 408.5 434.2413.5 417.0 392.2 423.2 417.3 415.6 414.1 429.8 dose [μg] FPD (St 3-F)173.6 184.0 179.1 181.8 184.0 186.1 177.0 180.1 177.0 193.2 183.1 174.7181.0 172.1 [μg] Group 1 186.2 172.6 185.2 179.5 180.3 195.9 182.6 185.6164.9 179.9 206.5 182.6 179.6 196.6 (MP-USP throat) [μg] Group 2 (St60.2 52.3 52.6 56.7 53.5 65.0 60.8 60.7 61.3 59.7 52.5 63.3 61.5 69.90-St 2) [μg] Group 3 (St 168.8 178.5 174.2 177.1 179.2 181.1 172.1 175.1172.4 188.6 178.1 170.7 176.6 168.5 3-St 5) [μg] Group 4 (St 4.9 5.5 5.04.7 4.8 5.0 4.8 5.0 4.6 4.7 5.0 3.9 4.4 3.7 6-F) [μg] Formoterol Metereddose 18.50 18.27 18.12 18.22 18.00 19.25 17.60 18.15 17.51 18.59 19.0518.42 18.21 18.43 [μg] Delivered 16.89 16.71 16.47 16.89 16.57 17.5416.34 16.76 16.05 17.13 16.56 17.04 16.76 16.81 dose FPD (St 3-F) 8.408.87 8.66 8.90 9.04 9.01 8.29 8.61 8.48 9.23 8.92 8.64 9.00 8.23 [μg]Group 1 8.06 7.61 7.67 7.42 7.21 8.16 7.30 7.49 7.01 7.42 8.44 7.72 7.238.03 (MP-USP throat) [μg] Group 2 (St 1.75 1.41 1.45 1.57 1.45 1.81 1.681.68 1.70 1.61 1.42 1.74 1.67 1.85 0-St 2) [μg] Group 3 (St 8.18 8.608.43 8.68 8.81 8.77 8.08 8.36 8.27 9.00 8.69 8.44 8.79 8.05 3-St 5) [μg]Group 4 (St 0.22 0.27 0.23 0.23 0.23 0.23 0.21 0.25 0.21 0.23 0.23 0.200.21 0.18 6-F) [μg]

TABLE 16 Summary of ACI results of fluticasone/formaterol formulationFlutiform 250/5 (Batch 5) up to 12 months at 25° C./60% RH and 40° C./75% RH. Each result is the mean of 6 determinations(beginning and endof 3 canisters). 25° C./60% RH 40° C./75% RH Fluticasone Initial 6months 12 months 1 month 6 months 12 months Metered dose [μg] 402.2432.1 426.9 433.0 420.3 419.0 417.1 431.4 428.9 417.9 Delivered dose[μg] 378.4 413.9 411.6 416.2 405.5 404.5 401.0 412.1 417.3 402.7 FPD (St3-F) [μg] 181.0 203.2 195.1 193.6 185.6 185.0 181.2 194.1 193.9 178.9Group 1 (MP-USP throat) [μg] 171.5 175.9 180.1 175.6 178.9 181.4 183.7179.9 175.5 171.2 Group 2 (St 0-St 2) [μg] 42.1 46.3 46.2 54.2 47.8 43.645.0 50.8 52.3 58.1 Group 3 (St 3-St 5) [μg] 177.1 199.1 190.8 189.9182.0 181.0 177.2 190.7 190.3 175.7 Group 4 (St 6-F) [μg] 3.8 4.0 4.43.7 3.6 4.0 4.0 3.4 3.5 3.2 Formoterol Metered dose [μg] 8.47 9.28 9.229.22 8.78 9.09 9.10 9.13 9.07 8.49 Delivered dose [μg] 7.62 8.38 8.408.45 8.03 8.36 8.26 8.23 8.37 7.76 FPD (St 3-F) [μg] 3.81 4.42 4.28 4.274.04 4.08 4.00 4.19 4.20 3.82 Group 1 (MP-USP throat) [μg] 3.78 3.914.01 3.84 3.79 4.04 4.14 3.94 3.84 3.59 Group 2 (St 0-St 2) [μg] 0.750.82 0.81 0.92 0.81 0.79 0.81 0.86 0.89 0.92 Group 3 (St 3-St 5) [μg]3.75 4.34 4.19 4.17 3.97 3.96 3.89 4.11 4.11 3.75 Group 4 (St 6-F) [μg]0.06 0.08 0.10 0.10 0.08 0.11 0.11 0.08 0.09 0.07

1-31. (canceled)
 32. A method for preparing a stabilized medicinalaerosol suspension formulation for MDI administration, the formulationcomprising: a) micronised formoterol fumarate dihydrate, or apharmaceutically acceptable salt thereof, in an amount of 0.003-0.008%by weight of the total weight of the formulation; b) micronisedfluticasone propionate or a pharmaceutically acceptable salt orderivative thereof in an amount of 0.01-0.6% by weight; c) asub-therapeutic quantity of a moisture-scavenger excipient comprisingsodium cromolyn in an amount of 0.01-0.1% by weight; and d) thepropellant is HFA 227, the method comprising incorporating (a), (b), and(c) into the propellant in relative amounts selected such that (a), (b),and (c) associate to form floccules having an average density the sameas the density of the HFA propellant ±0.2 g/cm³ and ensuring that thefloccules are formed by removing a portion of the suspension for visualinspection, agitating the portion of the suspension, visually inspectingthe agitated suspension for the formation of large loose flocculeswithin five minutes of cessation of agitation, and determining thatfloccules are formed if visual inspection identifies the large loosefloccules, wherein the floccules have a density substantially the sameas that of the HFA propellant, wherein the method provides a formulationhaving stability over a storage period from 3 to 18 months and the watercontent of the formulation after the storage period is in the range of500 ppm to 800 ppm.
 33. The method of claim 32, wherein the averagedensity of the floccules is the same as the density of the propellant,±0.1 g/cm³ or ±0.05 g/cm³.
 34. The method of claim 32, wherein thepropellant is HFA
 227. 35. The method of claim 32, wherein the amount of(a) is 0.004-0.008% w/w or 0.005-0.008% w/w.
 36. The method of claim 32,wherein the amount of (a) is 0.0071% w/w.
 37. The method of claim 32,wherein the amount of (b) is 0.02-0.5% w/w.
 38. The method of claim 32,wherein the amount of (b) is 0.03-0.4% w/w or 0.03-0.04%.
 39. The methodof claim 32, wherein the pharmaceutical suspension formulation furthercomprises a wetting agent.
 40. The method of claim 39, wherein thewetting agent is a dehydrated alcohol.
 41. The method of claim 40,wherein the dehydrated alcohol is ethanol.
 42. The method of claim 41,wherein the dehydrated alcohol is present in an amount of from 0.01 to3% by weight.
 43. The method of claim 41, wherein the dehydrated alcoholis present in an amount of from 0.05 to 2.5% by weight
 44. The method ofclaim 41, wherein the dehydrated alcohol is present in an amount of from1 to 2% by weight